The present invention relates to the surprising experimental findings that OBI-1 as described, supra, has 2-6 fold greater bioavailability compared to HYATE:C. Bioavailability refers to the blood levels achieved and maintained after administering a given dose. Bioavailability can be assessed by calculating the area under the curve (AUC) of blood levels plotted as a function of time after administration of a given dose. Consequently, compared to HYATE:C, OBI-1 can be administered at a substantially lower dose, expressed in Units/kg of body weight, to provide equivalent protection against serious bleeding episodes or in the prevention of bleeding episodes for hemophiliac patients who are in non-bleeding state. Alternatively, OBI-1 can be provided at the same dose as, or a similar dose to, HYATE C, but at a reduced frequency of administration compared to HYATE:C, bringing about more rapid control of bleeding and reducing the inconvenience associated with multiple administrations. Coupled with the fact that OBI-1 is available at a higher concentration in Units/ml than HYATE:C, the findings provide for a new method of administration that is highly advantageous for patients' well-being and quality of life. Current treatments with HYATE:C (100 Units/kg of body weight) typically require intravenous infusion of 280 ml of HYATE:C solution, at a rate of 2-5 ml per minute repeated every 6-8 hrs. Such treatments are tedious, can last 2 hours or more, and severely limit patient mobility and quality of life. By contrast, under the present invention, OBI-1 can be administered as a single intravenous injection of about 10-125 Units/kg body wt, at the rate of 1,000-10,000 Units/min. and may be required only one to four times, in order to halt a bleed, in contrast to HYATE:C, which takes a median of eight separate administrations over a two day period to halt a single bleeding episode, according to its package insert. When a hemophilia patient in need of such treatment has preexisting inhibitory antibodies to human fVIII that significantly cross-react with OBI-1, standard treatment, as applied using HYATE:C, would require more OBI-1 beyond the dosage given herein to neutralize the antibodies. Using OBI-1, faster control of bleeding is facilitated because higher fVIII levels can be achieved more rapidly. As will be discussed below, the actual dose administered to an individual depends on several individual factors including body weight, plasma volume, and residual antibody titer to OBI-1. The methods for calculating individual dosage have been well established from studies with HYATE:C. The methods for calculating OBI-1 dosage will, in addition, require taking into account the newly discovered greater in vivo efficacy and bioavailability of OBI-1. In an alternative embodiment of the invention, an antibody-neutralizing dose (“Loading Dose”) is omitted altogether, allowing for faster control of bleeding than heretofore available when following a standard administration method.
There are several reports of various methods to provide stable fVIII in a pharmaceutical composition or formulation. Albumin has often been used to stabilize these formulations. However, because of the cost and risk associated with using albumin as a stabilizer, there are several albumin-free pharmaceutical compositions containing fVIII in the art. For example, U.S. Pat. No. 5,565,427 describes fVIII compositions which contain an amino acid or its salts and a detergent such as polysorbate or TWEEN 80, or an organic polymer such as PEG; U.S. Pat. No. 5,605,884 discloses a fVIII composition in a high ionic strength media consisting of sodium chloride, calcium chloride and histidine; U.S. Pat. Nos. 5,763,401 and 5,874,408 disclose a recombinant fVIII composition containing glycine, histidine, sucrose, sodium chloride, and calcium chloride. There are further examples of fVIII compositions having various salts, non-ionic surfactants and antioxidants (U.S. Pat. Nos. 5,962,650, 5,972,885, WO 89/09784, and WO 94/07510). WO 03/080108 describes a stable solid pharmaceutical composition devoid of amino acids which contain fVIII, a surfactant, calcium chloride, sucrose, sodium chloride, trisodium citrate, and a buffer and has a pH of 6-8 prior to lyophilization and after reconstitution in water for injection.